Huntington's Disease Is a Fatal Syndrome Caused by a Mutation

Multiple Choice

Huntington's Disease is a fatal syndrome caused by a mutation in the HD gene. The disease has an average age of onset of 35 and the majority of individuals that are affected are heterozygotes. What is the probability that a 25 year old woman with no symptoms and who is the daughter of a man that has HD and a mother who does not will have a child that will have the mutant HD allele?

A) 25%
B) 50%
C) 75%
D) 100%